One of the myriad of ways we can advance artistically is to increase our awareness of the colours in the world around us, to pick out individual aspects and, more importantly, to have a way of remembering them. The task is a little bit like that faced by wine tasters who have to be able to identify or critique a particular wine from the little indications they encounter in taste. They develop a special vocabulary that matches up particular flavours to names they not only can recall, but can use when talking to others.

The first step to gaining a vocabulary of colours is to get hold of as many Colour Charts as possible. Preferably those hand painted with the manufacturer’s actual colours rather than something printed, or worse, viewed on your computer (when last did you calibrate your screen, if ever?). Look at them regularly, and pay particular attention to where companies have used the same name for slightly different colours. The pigment information will enable you to compare like with like. You’ll need to decide for yourself which particular colour you are going to associate with what name.

The next step is to use these colour names when you are looking at the world. Look at a bush and decide which colour greens. Look at the sea and the sky, and decide the particular colour blue, or grey, or green, you are seeing. The aim is to get to the stage where looking generates the names of specific paint colours in your mine e.g. “cerulean blue with a dark Prussian blue band on the horizon” rather than simply “blue sea”. (You can treat it like a game, and carry a suitable colour chart with you to check your accuracy. Holding your forefingers and thumbs together to create a tiny viewfinder will help you identify a colour in a small area.)
Finally, when you out sketching, rather than rely on colour matching with your watercolours, make a note of the particular colour you are seeing. Record how the changing light of the day causes the colours to vary; you can use this information to correct the time effects of plein air painting, or incorporate it into your choice of analogous colours when painting in with limited palette.
As you progress, you’ll find that you can differentiate between more and more shades of colour, developing a Nuanced Eye.
Know the name of the colour. Your name for that colour.
I can remember David and Bryce arguing to the death over the colour of a rose at Wimbledon. David – it’s red. Bryce – it’s orange. I could see both, and neither, and wondered about the name for that colour for a long time [years]. I now think it is scarlet. Do you remember the rose? It was by the gate. A long time ago, I know! Because I was trained as a dye chemist I felt I should know about the colour, but making up dyes to match colours is different to knowing the names of colours.
A rose like one of those fabrics where the warp and weft threads are different colours and the result is both colours yet neither. Cadmium red leans into yellow, but painting it orange and then glazing over or wet-on-wet with red would create variations in red/orange depending on cast and form shadows.